11.2 Troubleshooting the Hardware Box
11.2.12 Power supply issues
The power supply plays a vital role in the operation of any computer system. If the power supply is not working properly, the computer components will be receiving the wrong voltages and will not operate correctly. The power supply is attached to numerous devices that rely on it for power. The power supply converts the current coming from the wall jack from Alternating Current (AC) into Direct Current (DC). The AC coming from the wall is 120 or 240 V (depending on the country or region) and is converted into DC +/-5 and +/-12 V. After the current is converted from AC to DC, the power supply provides two important functions to the computer.
  • Supplies Power – The power supply is responsible for delivering the correct amount components. All of the system components are powered by the power supply. For example, the microprocessor, modular cards, RAM, and drives all receive DC from the power supply.
  • Acts as a Cooling Mechanism – This is the less obvious function of the power supply. However, this functionality should not be overlooked because it plays an important role in system performance. Computer systems perform better if they are properly ventilated and cooled. An onboard fan attached to most power supplies cools the power supply and internal components.

Tip: When a PC randomly reboots or locks up after running for a time, it may indicate a faulty power supply.